1. Field of the Invention
The present invention relates to a vacuum circuit breaker, and more particularly, to a main circuit terminal assembly for a vacuum circuit breaker.
2. Description of the Background Art
In general, a vacuum circuit breaker is an electrical device to protect load equipment and an electrical line from an overload or overcurrent which may occur in an electrical circuit due to an accident in the circuit (e.g., a short-circuit, or the like), by breaking the electrical circuit. Considering recent installation environment of such vacuum circuit breaker which requires a small installation area as well as a large capacity, a small-sized vacuum circuit breaker has been developed to conduct a large rated current therethrough. Accordingly, temperature increase of the vacuum circuit breaker by the large current has been considered as an important issue.
In the vacuum circuit breaker, a main circuit unit includes a vacuum interrupter having a fixed contact and a movable contact for opening or closing a circuit in a vacuum container, and a terminal unit for respectively being connected to the fixed contact and the movable contact of the vacuum interrupter and being connected to a circuit between a power source and an electrical load. In such main circuit unit, heat is mainly generated in a main conductive unit including a bus bar of the terminal unit, a connection terminal for a connection with the circuit, a clamp for connecting the bus bar to the vacuum interrupter.
However, in the main circuit terminal assembly for the conventional vacuum circuit breaker, the clamp does not have enough surface area as well as any means for effective heat radiation, thus to make it difficult to prevent temperature increase of a conductor.